<?php

namespace GetId3\Write;

use GetId3\Lib\Helper;
use GetId3\GetId3Core;
use GetId3\Module\Tag;

/////////////////////////////////////////////////////////////////
/// GetId3() by James Heinrich <info@getid3.org>               //
//  available at http://getid3.sourceforge.net                 //
//            or http://www.getid3.org                         //
/////////////////////////////////////////////////////////////////
// See readme.txt for more details                             //
/////////////////////////////////////////////////////////////////
///                                                            //
// write.id3v2.php                                             //
// module for writing ID3v2 tags                               //
// dependencies: module.tag.id3v2.php                          //
//                                                            ///
/////////////////////////////////////////////////////////////////

/**
 * module for writing ID3v2 tags
 *
 * @author James Heinrich <info@getid3.org>
 *
 * @link http://getid3.sourceforge.net
 * @link http://www.getid3.org
 *
 * @uses Tag\Id3v2
 */
class Id3v2
{
    public $filename;
    public $tag_data;
    /**
     * @var int
     */
    public $fread_buffer_size = 32768;    // read buffer size in bytes
    /**
     * @var int
     */
    public $paddedlength = 4096;     // minimum length of ID3v2 tag in bytes
    /**
     * @var int
     */
    public $majorversion = 3;        // ID3v2 major version (2, 3 (recommended), 4)
    /**
     * @var int
     */
    public $minorversion = 0;        // ID3v2 minor version - always 0
    /**
     * @var bool
     */
    public $merge_existing_data = false;    // if true, merge new data with existing tags; if false, delete old tag data and only write new tags
    /**
     * @var int
     */
    public $id3v2_default_encodingid = 0;        // default text encoding (ISO-8859-1) if not explicitly passed
    /**
     * @var bool
     */
    public $id3v2_use_unsynchronisation = false;    // the specs say it should be TRUE, but most other ID3v2-aware programs are broken if unsynchronization is used, so by default don't use it.
    /**
     * @var array
     */
    public $warnings = array();  // any non-critical errors will be stored here
    /**
     * @var array
     */
    public $errors = array();  // any critical errors will be stored here

    /**
     * @return bool
     */
    public function __construct()
    {
        return true;
    }

    /**
     * @return bool
     */
    public function WriteID3v2()
    {
        // File MUST be writeable - CHMOD(646) at least. It's best if the
        // directory is also writeable, because that method is both faster and less susceptible to errors.

        if (!empty($this->filename) && (is_writable($this->filename) || (!file_exists($this->filename) && is_writable(dirname($this->filename))))) {
            // Initialize GetId3 engine
            $getID3 = new GetId3Core();
            $OldThisFileInfo = $getID3->analyze($this->filename);
            if (!Helper::intValueSupported($OldThisFileInfo['filesize'])) {
                $this->errors[] = 'Unable to write ID3v2 because file is larger than '.round(PHP_INT_MAX / 1073741824).'GB';
                fclose($fp_source);

                return false;
            }
            if ($this->merge_existing_data) {
                // merge with existing data
                if (!empty($OldThisFileInfo['id3v2'])) {
                    $this->tag_data = $this->array_join_merge($OldThisFileInfo['id3v2'], $this->tag_data);
                }
            }
            $this->paddedlength = (isset($OldThisFileInfo['id3v2']['headerlength']) ? max($OldThisFileInfo['id3v2']['headerlength'], $this->paddedlength) : $this->paddedlength);

            if ($NewID3v2Tag = $this->GenerateID3v2Tag()) {
                if (file_exists($this->filename) && is_writable($this->filename) && isset($OldThisFileInfo['id3v2']['headerlength']) && ($OldThisFileInfo['id3v2']['headerlength'] == strlen($NewID3v2Tag))) {

                    // best and fastest method - insert-overwrite existing tag (padded to length of old tag if neccesary)
                    if (file_exists($this->filename)) {
                        if (is_readable($this->filename) && is_writable($this->filename) && is_file($this->filename) && ($fp = fopen($this->filename, 'r+b'))) {
                            rewind($fp);
                            fwrite($fp, $NewID3v2Tag, strlen($NewID3v2Tag));
                            fclose($fp);
                        } else {
                            $this->errors[] = 'Could not fopen("'.$this->filename.'", "r+b")';
                        }
                    } else {
                        if (is_writable($this->filename) && is_file($this->filename) && ($fp = fopen($this->filename, 'wb'))) {
                            rewind($fp);
                            fwrite($fp, $NewID3v2Tag, strlen($NewID3v2Tag));
                            fclose($fp);
                        } else {
                            $this->errors[] = 'Could not fopen("'.$this->filename.'", "wb")';
                        }
                    }
                } else {
                    if ($tempfilename = tempnam(GetId3Core::getTempDir(), 'getID3')) {
                        if (is_readable($this->filename) && is_file($this->filename) && ($fp_source = fopen($this->filename, 'rb'))) {
                            if (is_writable($tempfilename) && is_file($tempfilename) && ($fp_temp = fopen($tempfilename, 'wb'))) {
                                fwrite($fp_temp, $NewID3v2Tag, strlen($NewID3v2Tag));

                                rewind($fp_source);
                                if (!empty($OldThisFileInfo['avdataoffset'])) {
                                    fseek($fp_source, $OldThisFileInfo['avdataoffset'], SEEK_SET);
                                }

                                while ($buffer = fread($fp_source, $this->fread_buffer_size)) {
                                    fwrite($fp_temp, $buffer, strlen($buffer));
                                }

                                fclose($fp_temp);
                                fclose($fp_source);
                                copy($tempfilename, $this->filename);
                                unlink($tempfilename);

                                return true;
                            } else {
                                $this->errors[] = 'Could not fopen("'.$tempfilename.'", "wb")';
                            }
                            fclose($fp_source);
                        } else {
                            $this->errors[] = 'Could not fopen("'.$this->filename.'", "rb")';
                        }
                    }

                    return false;
                }
            } else {
                $this->errors[] = '$this->GenerateID3v2Tag() failed';
            }

            if (!empty($this->errors)) {
                return false;
            }

            return true;
        } else {
            $this->errors[] = 'WriteID3v2() failed: !is_writeable('.$this->filename.')';
        }

        return false;
    }

    public function RemoveID3v2()
    {
        // File MUST be writeable - CHMOD(646) at least. It's best if the
        // directory is also writeable, because that method is both faster and less susceptible to errors.
        if (is_writable(dirname($this->filename))) {

            // preferred method - only one copying operation, minimal chance of corrupting
            // original file if script is interrupted, but required directory to be writeable
            if (is_readable($this->filename) && is_file($this->filename) && ($fp_source = fopen($this->filename, 'rb'))) {

                // Initialize GetId3 engine
                $getID3 = new GetId3Core();
                $OldThisFileInfo = $getID3->analyze($this->filename);
                if (!Helper::intValueSupported($OldThisFileInfo['filesize'])) {
                    $this->errors[] = 'Unable to remove ID3v2 because file is larger than '.round(PHP_INT_MAX / 1073741824).'GB';
                    fclose($fp_source);

                    return false;
                }
                rewind($fp_source);
                if ($OldThisFileInfo['avdataoffset'] !== false) {
                    fseek($fp_source, $OldThisFileInfo['avdataoffset'], SEEK_SET);
                }
                if (is_writable($this->filename) && is_file($this->filename) && ($fp_temp = fopen($this->filename.'getid3tmp', 'w+b'))) {
                    while ($buffer = fread($fp_source, $this->fread_buffer_size)) {
                        fwrite($fp_temp, $buffer, strlen($buffer));
                    }
                    fclose($fp_temp);
                } else {
                    $this->errors[] = 'Could not fopen("'.$this->filename.'getid3tmp", "w+b")';
                }
                fclose($fp_source);
            } else {
                $this->errors[] = 'Could not fopen("'.$this->filename.'", "rb")';
            }
            if (file_exists($this->filename)) {
                unlink($this->filename);
            }
            rename($this->filename.'getid3tmp', $this->filename);
        } elseif (is_writable($this->filename)) {

            // less desirable alternate method - double-copies the file, overwrites original file
            // and could corrupt source file if the script is interrupted or an error occurs.
            if (is_readable($this->filename) && is_file($this->filename) && ($fp_source = fopen($this->filename, 'rb'))) {

                // Initialize GetId3 engine
                $getID3 = new GetId3Core();
                $OldThisFileInfo = $getID3->analyze($this->filename);
                if (!Helper::intValueSupported($OldThisFileInfo['filesize'])) {
                    $this->errors[] = 'Unable to remove ID3v2 because file is larger than '.round(PHP_INT_MAX / 1073741824).'GB';
                    fclose($fp_source);

                    return false;
                }
                rewind($fp_source);
                if ($OldThisFileInfo['avdataoffset'] !== false) {
                    fseek($fp_source, $OldThisFileInfo['avdataoffset'], SEEK_SET);
                }
                if ($fp_temp = tmpfile()) {
                    while ($buffer = fread($fp_source, $this->fread_buffer_size)) {
                        fwrite($fp_temp, $buffer, strlen($buffer));
                    }
                    fclose($fp_source);
                    if (is_writable($this->filename) && is_file($this->filename) && ($fp_source = fopen($this->filename, 'wb'))) {
                        rewind($fp_temp);
                        while ($buffer = fread($fp_temp, $this->fread_buffer_size)) {
                            fwrite($fp_source, $buffer, strlen($buffer));
                        }
                        fseek($fp_temp, -128, SEEK_END);
                        fclose($fp_source);
                    } else {
                        $this->errors[] = 'Could not fopen("'.$this->filename.'", "wb")';
                    }
                    fclose($fp_temp);
                } else {
                    $this->errors[] = 'Could not create tmpfile()';
                }
            } else {
                $this->errors[] = 'Could not fopen("'.$this->filename.'", "rb")';
            }
        } else {
            $this->errors[] = 'Directory and file both not writeable';
        }

        if (!empty($this->errors)) {
            return false;
        }

        return true;
    }

    /**
     * @param  type    $flags
     *
     * @return bool
     */
    public function GenerateID3v2TagFlags($flags)
    {
        switch ($this->majorversion) {
            case 4:
                // %abcd0000
                $flag = (!empty($flags['unsynchronisation']) ? '1' : '0'); // a - Unsynchronisation
                $flag .= (!empty($flags['extendedheader']) ? '1' : '0'); // b - Extended header
                $flag .= (!empty($flags['experimental']) ? '1' : '0'); // c - Experimental indicator
                $flag .= (!empty($flags['footer']) ? '1' : '0'); // d - Footer present
                $flag .= '0000';
                break;

            case 3:
                // %abc00000
                $flag = (!empty($flags['unsynchronisation']) ? '1' : '0'); // a - Unsynchronisation
                $flag .= (!empty($flags['extendedheader']) ? '1' : '0'); // b - Extended header
                $flag .= (!empty($flags['experimental']) ? '1' : '0'); // c - Experimental indicator
                $flag .= '00000';
                break;

            case 2:
                // %ab000000
                $flag = (!empty($flags['unsynchronisation']) ? '1' : '0'); // a - Unsynchronisation
                $flag .= (!empty($flags['compression']) ? '1' : '0'); // b - Compression
                $flag .= '000000';
                break;

            default:
                return false;
                break;
        }

        return chr(bindec($flag));
    }

    /**
     * @param  type    $TagAlter
     * @param  type    $FileAlter
     * @param  type    $ReadOnly
     * @param  type    $Compression
     * @param  type    $Encryption
     * @param  type    $GroupingIdentity
     * @param  type    $Unsynchronisation
     * @param  type    $DataLengthIndicator
     *
     * @return bool
     */
    public function GenerateID3v2FrameFlags($TagAlter = false, $FileAlter = false, $ReadOnly = false, $Compression = false, $Encryption = false, $GroupingIdentity = false, $Unsynchronisation = false, $DataLengthIndicator = false)
    {
        switch ($this->majorversion) {
            case 4:
                // %0abc0000 %0h00kmnp
                $flag1 = '0';
                $flag1 .= $TagAlter  ? '1' : '0'; // a - Tag alter preservation (true == discard)
                $flag1 .= $FileAlter ? '1' : '0'; // b - File alter preservation (true == discard)
                $flag1 .= $ReadOnly  ? '1' : '0'; // c - Read only (true == read only)
                $flag1 .= '0000';

                $flag2 = '0';
                $flag2 .= $GroupingIdentity    ? '1' : '0'; // h - Grouping identity (true == contains group information)
                $flag2 .= '00';
                $flag2 .= $Compression         ? '1' : '0'; // k - Compression (true == compressed)
                $flag2 .= $Encryption          ? '1' : '0'; // m - Encryption (true == encrypted)
                $flag2 .= $Unsynchronisation   ? '1' : '0'; // n - Unsynchronisation (true == unsynchronised)
                $flag2 .= $DataLengthIndicator ? '1' : '0'; // p - Data length indicator (true == data length indicator added)
                break;

            case 3:
                // %abc00000 %ijk00000
                $flag1 = $TagAlter  ? '1' : '0';  // a - Tag alter preservation (true == discard)
                $flag1 .= $FileAlter ? '1' : '0';  // b - File alter preservation (true == discard)
                $flag1 .= $ReadOnly  ? '1' : '0';  // c - Read only (true == read only)
                $flag1 .= '00000';

                $flag2 = $Compression      ? '1' : '0';      // i - Compression (true == compressed)
                $flag2 .= $Encryption       ? '1' : '0';      // j - Encryption (true == encrypted)
                $flag2 .= $GroupingIdentity ? '1' : '0';      // k - Grouping identity (true == contains group information)
                $flag2 .= '00000';
                break;

            default:
                return false;
                break;

        }

        return chr(bindec($flag1)).chr(bindec($flag2));
    }

    /**
     * @param  type    $frame_name
     * @param  type    $source_data_array
     *
     * @return bool
     */
    public function GenerateID3v2FrameData($frame_name, $source_data_array)
    {
        if (!Tag\Id3v2::IsValidID3v2FrameName($frame_name, $this->majorversion)) {
            return false;
        }
        $framedata = '';

        if (($this->majorversion < 3) || ($this->majorversion > 4)) {
            $this->errors[] = 'Only ID3v2.3 and ID3v2.4 are supported in GenerateID3v2FrameData()';
        } else { // $this->majorversion 3 or 4

            switch ($frame_name) {
                case 'UFID':
                    // 4.1   UFID Unique file identifier
                    // Owner identifier        <text string> $00
                    // Identifier              <up to 64 bytes binary data>
                    if (strlen($source_data_array['data']) > 64) {
                        $this->errors[] = 'Identifier not allowed to be longer than 64 bytes in '.$frame_name.' (supplied data was '.strlen($source_data_array['data']).' bytes long)';
                    } else {
                        $framedata .= str_replace("\x00", '', $source_data_array['ownerid'])."\x00";
                        $framedata .= substr($source_data_array['data'], 0, 64); // max 64 bytes - truncate anything longer
                    }
                    break;

                case 'TXXX':
                    // 4.2.2 TXXX User defined text information frame
                    // Text encoding     $xx
                    // Description       <text string according to encoding> $00 (00)
                    // Value             <text string according to encoding>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'], $this->majorversion)) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= $source_data_array['description'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'WXXX':
                    // 4.3.2 WXXX User defined URL link frame
                    // Text encoding     $xx
                    // Description       <text string according to encoding> $00 (00)
                    // URL               <text string>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'], $this->majorversion)) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                    } elseif (!isset($source_data_array['data']) || !$this->IsValidURL($source_data_array['data'], false, false)) {
                        //$this->errors[] = 'Invalid URL in '.$frame_name.' ('.$source_data_array['data'].')';
                        // probably should be an error, need to rewrite IsValidURL() to handle other encodings
                        $this->warnings[] = 'Invalid URL in '.$frame_name.' ('.$source_data_array['data'].')';
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= $source_data_array['description'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'IPLS':
                    // 4.4  IPLS Involved people list (ID3v2.3 only)
                    // Text encoding     $xx
                    // People list strings    <textstrings>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'], $this->majorversion)) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'MCDI':
                    // 4.4   MCDI Music CD identifier
                    // CD TOC                <binary data>
                    $framedata .= $source_data_array['data'];
                    break;

                case 'ETCO':
                    // 4.5   ETCO Event timing codes
                    // Time stamp format    $xx
                    //   Where time stamp format is:
                    // $01  (32-bit value) MPEG frames from beginning of file
                    // $02  (32-bit value) milliseconds from beginning of file
                    //   Followed by a list of key events in the following format:
                    // Type of event   $xx
                    // Time stamp      $xx (xx ...)
                    //   The 'Time stamp' is set to zero if directly at the beginning of the sound
                    //   or after the previous event. All events MUST be sorted in chronological order.
                    if (($source_data_array['timestampformat'] > 2) || ($source_data_array['timestampformat'] < 1)) {
                        $this->errors[] = 'Invalid Time Stamp Format byte in '.$frame_name.' ('.$source_data_array['timestampformat'].')';
                    } else {
                        $framedata .= chr($source_data_array['timestampformat']);
                        foreach ($source_data_array as $key => $val) {
                            if (!$this->ID3v2IsValidETCOevent($val['typeid'])) {
                                $this->errors[] = 'Invalid Event Type byte in '.$frame_name.' ('.$val['typeid'].')';
                            } elseif (($key != 'timestampformat') && ($key != 'flags')) {
                                if (($val['timestamp'] > 0) && ($previousETCOtimestamp >= $val['timestamp'])) {
                                    //   The 'Time stamp' is set to zero if directly at the beginning of the sound
                                    //   or after the previous event. All events MUST be sorted in chronological order.
                                    $this->errors[] = 'Out-of-order timestamp in '.$frame_name.' ('.$val['timestamp'].') for Event Type ('.$val['typeid'].')';
                                } else {
                                    $framedata .= chr($val['typeid']);
                                    $framedata .= Helper::BigEndian2String($val['timestamp'], 4, false);
                                }
                            }
                        }
                    }
                    break;

                case 'MLLT':
                    // 4.6   MLLT MPEG location lookup table
                    // MPEG frames between reference  $xx xx
                    // Bytes between reference        $xx xx xx
                    // Milliseconds between reference $xx xx xx
                    // Bits for bytes deviation       $xx
                    // Bits for milliseconds dev.     $xx
                    //   Then for every reference the following data is included;
                    // Deviation in bytes         %xxx....
                    // Deviation in milliseconds  %xxx....
                    if (($source_data_array['framesbetweenreferences'] > 0) && ($source_data_array['framesbetweenreferences'] <= 65535)) {
                        $framedata .= Helper::BigEndian2String($source_data_array['framesbetweenreferences'], 2, false);
                    } else {
                        $this->errors[] = 'Invalid MPEG Frames Between References in '.$frame_name.' ('.$source_data_array['framesbetweenreferences'].')';
                    }
                    if (($source_data_array['bytesbetweenreferences'] > 0) && ($source_data_array['bytesbetweenreferences'] <= 16777215)) {
                        $framedata .= Helper::BigEndian2String($source_data_array['bytesbetweenreferences'], 3, false);
                    } else {
                        $this->errors[] = 'Invalid bytes Between References in '.$frame_name.' ('.$source_data_array['bytesbetweenreferences'].')';
                    }
                    if (($source_data_array['msbetweenreferences'] > 0) && ($source_data_array['msbetweenreferences'] <= 16777215)) {
                        $framedata .= Helper::BigEndian2String($source_data_array['msbetweenreferences'], 3, false);
                    } else {
                        $this->errors[] = 'Invalid Milliseconds Between References in '.$frame_name.' ('.$source_data_array['msbetweenreferences'].')';
                    }
                    if (!$this->IsWithinBitRange($source_data_array['bitsforbytesdeviation'], 8, false)) {
                        if (($source_data_array['bitsforbytesdeviation'] % 4) == 0) {
                            $framedata .= chr($source_data_array['bitsforbytesdeviation']);
                        } else {
                            $this->errors[] = 'Bits For Bytes Deviation in '.$frame_name.' ('.$source_data_array['bitsforbytesdeviation'].') must be a multiple of 4.';
                        }
                    } else {
                        $this->errors[] = 'Invalid Bits For Bytes Deviation in '.$frame_name.' ('.$source_data_array['bitsforbytesdeviation'].')';
                    }
                    if (!$this->IsWithinBitRange($source_data_array['bitsformsdeviation'], 8, false)) {
                        if (($source_data_array['bitsformsdeviation'] % 4) == 0) {
                            $framedata .= chr($source_data_array['bitsformsdeviation']);
                        } else {
                            $this->errors[] = 'Bits For Milliseconds Deviation in '.$frame_name.' ('.$source_data_array['bitsforbytesdeviation'].') must be a multiple of 4.';
                        }
                    } else {
                        $this->errors[] = 'Invalid Bits For Milliseconds Deviation in '.$frame_name.' ('.$source_data_array['bitsformsdeviation'].')';
                    }
                    foreach ($source_data_array as $key => $val) {
                        if (($key != 'framesbetweenreferences') && ($key != 'bytesbetweenreferences') && ($key != 'msbetweenreferences') && ($key != 'bitsforbytesdeviation') && ($key != 'bitsformsdeviation') && ($key != 'flags')) {
                            $unwrittenbitstream .= str_pad(Helper::Dec2Bin($val['bytedeviation']), $source_data_array['bitsforbytesdeviation'], '0', STR_PAD_LEFT);
                            $unwrittenbitstream .= str_pad(Helper::Dec2Bin($val['msdeviation']), $source_data_array['bitsformsdeviation'], '0', STR_PAD_LEFT);
                        }
                    }
                    for ($i = 0; $i < strlen($unwrittenbitstream); $i += 8) {
                        $highnibble = bindec(substr($unwrittenbitstream, $i, 4)) << 4;
                        $lownibble = bindec(substr($unwrittenbitstream, $i + 4, 4));
                        $framedata .= chr($highnibble & $lownibble);
                    }
                    break;

                case 'SYTC':
                    // 4.7   SYTC Synchronised tempo codes
                    // Time stamp format   $xx
                    // Tempo data          <binary data>
                    //   Where time stamp format is:
                    // $01  (32-bit value) MPEG frames from beginning of file
                    // $02  (32-bit value) milliseconds from beginning of file
                    if (($source_data_array['timestampformat'] > 2) || ($source_data_array['timestampformat'] < 1)) {
                        $this->errors[] = 'Invalid Time Stamp Format byte in '.$frame_name.' ('.$source_data_array['timestampformat'].')';
                    } else {
                        $framedata .= chr($source_data_array['timestampformat']);
                        foreach ($source_data_array as $key => $val) {
                            if (!$this->ID3v2IsValidETCOevent($val['typeid'])) {
                                $this->errors[] = 'Invalid Event Type byte in '.$frame_name.' ('.$val['typeid'].')';
                            } elseif (($key != 'timestampformat') && ($key != 'flags')) {
                                if (($val['tempo'] < 0) || ($val['tempo'] > 510)) {
                                    $this->errors[] = 'Invalid Tempo (max = 510) in '.$frame_name.' ('.$val['tempo'].') at timestamp ('.$val['timestamp'].')';
                                } else {
                                    if ($val['tempo'] > 255) {
                                        $framedata .= chr(255);
                                        $val['tempo'] -= 255;
                                    }
                                    $framedata .= chr($val['tempo']);
                                    $framedata .= Helper::BigEndian2String($val['timestamp'], 4, false);
                                }
                            }
                        }
                    }
                    break;

                case 'USLT':
                    // 4.8   USLT Unsynchronised lyric/text transcription
                    // Text encoding        $xx
                    // Language             $xx xx xx
                    // Content descriptor   <text string according to encoding> $00 (00)
                    // Lyrics/text          <full text string according to encoding>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                    } elseif (Tag\Id3v2::LanguageLookup($source_data_array['language'], true) == '') {
                        $this->errors[] = 'Invalid Language in '.$frame_name.' ('.$source_data_array['language'].')';
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= strtolower($source_data_array['language']);
                        $framedata .= $source_data_array['description'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'SYLT':
                    // 4.9   SYLT Synchronised lyric/text
                    // Text encoding        $xx
                    // Language             $xx xx xx
                    // Time stamp format    $xx
                    //   $01  (32-bit value) MPEG frames from beginning of file
                    //   $02  (32-bit value) milliseconds from beginning of file
                    // Content type         $xx
                    // Content descriptor   <text string according to encoding> $00 (00)
                    //   Terminated text to be synced (typically a syllable)
                    //   Sync identifier (terminator to above string)   $00 (00)
                    //   Time stamp                                     $xx (xx ...)
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                    } elseif (Tag\Id3v2::LanguageLookup($source_data_array['language'], true) == '') {
                        $this->errors[] = 'Invalid Language in '.$frame_name.' ('.$source_data_array['language'].')';
                    } elseif (($source_data_array['timestampformat'] > 2) || ($source_data_array['timestampformat'] < 1)) {
                        $this->errors[] = 'Invalid Time Stamp Format byte in '.$frame_name.' ('.$source_data_array['timestampformat'].')';
                    } elseif (!$this->ID3v2IsValidSYLTtype($source_data_array['contenttypeid'])) {
                        $this->errors[] = 'Invalid Content Type byte in '.$frame_name.' ('.$source_data_array['contenttypeid'].')';
                    } elseif (!is_array($source_data_array['data'])) {
                        $this->errors[] = 'Invalid Lyric/Timestamp data in '.$frame_name.' (must be an array)';
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= strtolower($source_data_array['language']);
                        $framedata .= chr($source_data_array['timestampformat']);
                        $framedata .= chr($source_data_array['contenttypeid']);
                        $framedata .= $source_data_array['description'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        ksort($source_data_array['data']);
                        foreach ($source_data_array['data'] as $key => $val) {
                            $framedata .= $val['data'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                            $framedata .= Helper::BigEndian2String($val['timestamp'], 4, false);
                        }
                    }
                    break;

                case 'COMM':
                    // 4.10  COMM Comments
                    // Text encoding          $xx
                    // Language               $xx xx xx
                    // Short content descrip. <text string according to encoding> $00 (00)
                    // The actual text        <full text string according to encoding>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                    } elseif (Tag\Id3v2::LanguageLookup($source_data_array['language'], true) == '') {
                        $this->errors[] = 'Invalid Language in '.$frame_name.' ('.$source_data_array['language'].')';
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= strtolower($source_data_array['language']);
                        $framedata .= $source_data_array['description'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'RVA2':
                    // 4.11  RVA2 Relative volume adjustment (2) (ID3v2.4+ only)
                    // Identification          <text string> $00
                    //   The 'identification' string is used to identify the situation and/or
                    //   device where this adjustment should apply. The following is then
                    //   repeated for every channel:
                    // Type of channel         $xx
                    // Volume adjustment       $xx xx
                    // Bits representing peak  $xx
                    // Peak volume             $xx (xx ...)
                    $framedata .= str_replace("\x00", '', $source_data_array['description'])."\x00";
                    foreach ($source_data_array as $key => $val) {
                        if ($key != 'description') {
                            $framedata .= chr($val['channeltypeid']);
                            $framedata .= Helper::BigEndian2String($val['volumeadjust'], 2, false, true); // signed 16-bit
                            if (!$this->IsWithinBitRange($source_data_array['bitspeakvolume'], 8, false)) {
                                $framedata .= chr($val['bitspeakvolume']);
                                if ($val['bitspeakvolume'] > 0) {
                                    $framedata .= Helper::BigEndian2String($val['peakvolume'], ceil($val['bitspeakvolume'] / 8), false, false);
                                }
                            } else {
                                $this->errors[] = 'Invalid Bits Representing Peak Volume in '.$frame_name.' ('.$val['bitspeakvolume'].') (range = 0 to 255)';
                            }
                        }
                    }
                    break;

                case 'RVAD':
                    // 4.12  RVAD Relative volume adjustment (ID3v2.3 only)
                    // Increment/decrement     %00fedcba
                    // Bits used for volume descr.        $xx
                    // Relative volume change, right      $xx xx (xx ...) // a
                    // Relative volume change, left       $xx xx (xx ...) // b
                    // Peak volume right                  $xx xx (xx ...)
                    // Peak volume left                   $xx xx (xx ...)
                    // Relative volume change, right back $xx xx (xx ...) // c
                    // Relative volume change, left back  $xx xx (xx ...) // d
                    // Peak volume right back             $xx xx (xx ...)
                    // Peak volume left back              $xx xx (xx ...)
                    // Relative volume change, center     $xx xx (xx ...) // e
                    // Peak volume center                 $xx xx (xx ...)
                    // Relative volume change, bass       $xx xx (xx ...) // f
                    // Peak volume bass                   $xx xx (xx ...)
                    if (!$this->IsWithinBitRange($source_data_array['bitsvolume'], 8, false)) {
                        $this->errors[] = 'Invalid Bits For Volume Description byte in '.$frame_name.' ('.$source_data_array['bitsvolume'].') (range = 1 to 255)';
                    } else {
                        $incdecflag .= '00';
                        $incdecflag .= $source_data_array['incdec']['right']     ? '1' : '0';     // a - Relative volume change, right
                        $incdecflag .= $source_data_array['incdec']['left']      ? '1' : '0';      // b - Relative volume change, left
                        $incdecflag .= $source_data_array['incdec']['rightrear'] ? '1' : '0'; // c - Relative volume change, right back
                        $incdecflag .= $source_data_array['incdec']['leftrear']  ? '1' : '0';  // d - Relative volume change, left back
                        $incdecflag .= $source_data_array['incdec']['center']    ? '1' : '0';    // e - Relative volume change, center
                        $incdecflag .= $source_data_array['incdec']['bass']      ? '1' : '0';      // f - Relative volume change, bass
                        $framedata .= chr(bindec($incdecflag));
                        $framedata .= chr($source_data_array['bitsvolume']);
                        $framedata .= Helper::BigEndian2String($source_data_array['volumechange']['right'], ceil($source_data_array['bitsvolume'] / 8), false);
                        $framedata .= Helper::BigEndian2String($source_data_array['volumechange']['left'], ceil($source_data_array['bitsvolume'] / 8), false);
                        $framedata .= Helper::BigEndian2String($source_data_array['peakvolume']['right'], ceil($source_data_array['bitsvolume'] / 8), false);
                        $framedata .= Helper::BigEndian2String($source_data_array['peakvolume']['left'], ceil($source_data_array['bitsvolume'] / 8), false);
                        if ($source_data_array['volumechange']['rightrear'] || $source_data_array['volumechange']['leftrear'] ||
                            $source_data_array['peakvolume']['rightrear'] || $source_data_array['peakvolume']['leftrear'] ||
                            $source_data_array['volumechange']['center'] || $source_data_array['peakvolume']['center'] ||
                            $source_data_array['volumechange']['bass'] || $source_data_array['peakvolume']['bass']) {
                            $framedata .= Helper::BigEndian2String($source_data_array['volumechange']['rightrear'], ceil($source_data_array['bitsvolume'] / 8), false);
                            $framedata .= Helper::BigEndian2String($source_data_array['volumechange']['leftrear'], ceil($source_data_array['bitsvolume'] / 8), false);
                            $framedata .= Helper::BigEndian2String($source_data_array['peakvolume']['rightrear'], ceil($source_data_array['bitsvolume'] / 8), false);
                            $framedata .= Helper::BigEndian2String($source_data_array['peakvolume']['leftrear'], ceil($source_data_array['bitsvolume'] / 8), false);
                        }
                        if ($source_data_array['volumechange']['center'] || $source_data_array['peakvolume']['center'] ||
                            $source_data_array['volumechange']['bass'] || $source_data_array['peakvolume']['bass']) {
                            $framedata .= Helper::BigEndian2String($source_data_array['volumechange']['center'], ceil($source_data_array['bitsvolume'] / 8), false);
                            $framedata .= Helper::BigEndian2String($source_data_array['peakvolume']['center'], ceil($source_data_array['bitsvolume'] / 8), false);
                        }
                        if ($source_data_array['volumechange']['bass'] || $source_data_array['peakvolume']['bass']) {
                            $framedata .= Helper::BigEndian2String($source_data_array['volumechange']['bass'], ceil($source_data_array['bitsvolume'] / 8), false);
                            $framedata .= Helper::BigEndian2String($source_data_array['peakvolume']['bass'], ceil($source_data_array['bitsvolume'] / 8), false);
                        }
                    }
                    break;

                case 'EQU2':
                    // 4.12  EQU2 Equalisation (2) (ID3v2.4+ only)
                    // Interpolation method  $xx
                    //   $00  Band
                    //   $01  Linear
                    // Identification        <text string> $00
                    //   The following is then repeated for every adjustment point
                    // Frequency          $xx xx
                    // Volume adjustment  $xx xx
                    if (($source_data_array['interpolationmethod'] < 0) || ($source_data_array['interpolationmethod'] > 1)) {
                        $this->errors[] = 'Invalid Interpolation Method byte in '.$frame_name.' ('.$source_data_array['interpolationmethod'].') (valid = 0 or 1)';
                    } else {
                        $framedata .= chr($source_data_array['interpolationmethod']);
                        $framedata .= str_replace("\x00", '', $source_data_array['description'])."\x00";
                        foreach ($source_data_array['data'] as $key => $val) {
                            $framedata .= Helper::BigEndian2String(intval(round($key * 2)), 2, false);
                            $framedata .= Helper::BigEndian2String($val, 2, false, true); // signed 16-bit
                        }
                    }
                    break;

                case 'EQUA':
                    // 4.12  EQUA Equalisation (ID3v2.3 only)
                    // Adjustment bits    $xx
                    //   This is followed by 2 bytes + ('adjustment bits' rounded up to the
                    //   nearest byte) for every equalisation band in the following format,
                    //   giving a frequency range of 0 - 32767Hz:
                    // Increment/decrement   %x (MSB of the Frequency)
                    // Frequency             (lower 15 bits)
                    // Adjustment            $xx (xx ...)
                    if (!$this->IsWithinBitRange($source_data_array['bitsvolume'], 8, false)) {
                        $this->errors[] = 'Invalid Adjustment Bits byte in '.$frame_name.' ('.$source_data_array['bitsvolume'].') (range = 1 to 255)';
                    } else {
                        $framedata .= chr($source_data_array['adjustmentbits']);
                        foreach ($source_data_array as $key => $val) {
                            if ($key != 'bitsvolume') {
                                if (($key > 32767) || ($key < 0)) {
                                    $this->errors[] = 'Invalid Frequency in '.$frame_name.' ('.$key.') (range = 0 to 32767)';
                                } else {
                                    if ($val >= 0) {
                                        // put MSB of frequency to 1 if increment, 0 if decrement
                                        $key |= 0x8000;
                                    }
                                    $framedata .= Helper::BigEndian2String($key, 2, false);
                                    $framedata .= Helper::BigEndian2String($val, ceil($source_data_array['adjustmentbits'] / 8), false);
                                }
                            }
                        }
                    }
                    break;

                case 'RVRB':
                    // 4.13  RVRB Reverb
                    // Reverb left (ms)                 $xx xx
                    // Reverb right (ms)                $xx xx
                    // Reverb bounces, left             $xx
                    // Reverb bounces, right            $xx
                    // Reverb feedback, left to left    $xx
                    // Reverb feedback, left to right   $xx
                    // Reverb feedback, right to right  $xx
                    // Reverb feedback, right to left   $xx
                    // Premix left to right             $xx
                    // Premix right to left             $xx
                    if (!$this->IsWithinBitRange($source_data_array['left'], 16, false)) {
                        $this->errors[] = 'Invalid Reverb Left in '.$frame_name.' ('.$source_data_array['left'].') (range = 0 to 65535)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['right'], 16, false)) {
                        $this->errors[] = 'Invalid Reverb Left in '.$frame_name.' ('.$source_data_array['right'].') (range = 0 to 65535)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['bouncesL'], 8, false)) {
                        $this->errors[] = 'Invalid Reverb Bounces, Left in '.$frame_name.' ('.$source_data_array['bouncesL'].') (range = 0 to 255)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['bouncesR'], 8, false)) {
                        $this->errors[] = 'Invalid Reverb Bounces, Right in '.$frame_name.' ('.$source_data_array['bouncesR'].') (range = 0 to 255)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['feedbackLL'], 8, false)) {
                        $this->errors[] = 'Invalid Reverb Feedback, Left-To-Left in '.$frame_name.' ('.$source_data_array['feedbackLL'].') (range = 0 to 255)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['feedbackLR'], 8, false)) {
                        $this->errors[] = 'Invalid Reverb Feedback, Left-To-Right in '.$frame_name.' ('.$source_data_array['feedbackLR'].') (range = 0 to 255)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['feedbackRR'], 8, false)) {
                        $this->errors[] = 'Invalid Reverb Feedback, Right-To-Right in '.$frame_name.' ('.$source_data_array['feedbackRR'].') (range = 0 to 255)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['feedbackRL'], 8, false)) {
                        $this->errors[] = 'Invalid Reverb Feedback, Right-To-Left in '.$frame_name.' ('.$source_data_array['feedbackRL'].') (range = 0 to 255)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['premixLR'], 8, false)) {
                        $this->errors[] = 'Invalid Premix, Left-To-Right in '.$frame_name.' ('.$source_data_array['premixLR'].') (range = 0 to 255)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['premixRL'], 8, false)) {
                        $this->errors[] = 'Invalid Premix, Right-To-Left in '.$frame_name.' ('.$source_data_array['premixRL'].') (range = 0 to 255)';
                    } else {
                        $framedata .= Helper::BigEndian2String($source_data_array['left'], 2, false);
                        $framedata .= Helper::BigEndian2String($source_data_array['right'], 2, false);
                        $framedata .= chr($source_data_array['bouncesL']);
                        $framedata .= chr($source_data_array['bouncesR']);
                        $framedata .= chr($source_data_array['feedbackLL']);
                        $framedata .= chr($source_data_array['feedbackLR']);
                        $framedata .= chr($source_data_array['feedbackRR']);
                        $framedata .= chr($source_data_array['feedbackRL']);
                        $framedata .= chr($source_data_array['premixLR']);
                        $framedata .= chr($source_data_array['premixRL']);
                    }
                    break;

                case 'APIC':
                    // 4.14  APIC Attached picture
                    // Text encoding      $xx
                    // MIME type          <text string> $00
                    // Picture type       $xx
                    // Description        <text string according to encoding> $00 (00)
                    // Picture data       <binary data>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                    } elseif (!$this->ID3v2IsValidAPICpicturetype($source_data_array['picturetypeid'])) {
                        $this->errors[] = 'Invalid Picture Type byte in '.$frame_name.' ('.$source_data_array['picturetypeid'].') for ID3v2.'.$this->majorversion;
                    } elseif (($this->majorversion >= 3) && (!$this->ID3v2IsValidAPICimageformat($source_data_array['mime']))) {
                        $this->errors[] = 'Invalid MIME Type in '.$frame_name.' ('.$source_data_array['mime'].') for ID3v2.'.$this->majorversion;
                    } elseif (($source_data_array['mime'] == '-->') && (!$this->IsValidURL($source_data_array['data'], false, false))) {
                        //$this->errors[] = 'Invalid URL in '.$frame_name.' ('.$source_data_array['data'].')';
                        // probably should be an error, need to rewrite IsValidURL() to handle other encodings
                        $this->warnings[] = 'Invalid URL in '.$frame_name.' ('.$source_data_array['data'].')';
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= str_replace("\x00", '', $source_data_array['mime'])."\x00";
                        $framedata .= chr($source_data_array['picturetypeid']);
                        $framedata .= (!empty($source_data_array['description']) ? $source_data_array['description'] : '').Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'GEOB':
                    // 4.15  GEOB General encapsulated object
                    // Text encoding          $xx
                    // MIME type              <text string> $00
                    // Filename               <text string according to encoding> $00 (00)
                    // Content description    <text string according to encoding> $00 (00)
                    // Encapsulated object    <binary data>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                    } elseif (!$this->IsValidMIMEstring($source_data_array['mime'])) {
                        $this->errors[] = 'Invalid MIME Type in '.$frame_name.' ('.$source_data_array['mime'].')';
                    } elseif (!$source_data_array['description']) {
                        $this->errors[] = 'Missing Description in '.$frame_name;
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= str_replace("\x00", '', $source_data_array['mime'])."\x00";
                        $framedata .= $source_data_array['filename'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['description'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'PCNT':
                    // 4.16  PCNT Play counter
                    //   When the counter reaches all one's, one byte is inserted in
                    //   front of the counter thus making the counter eight bits bigger
                    // Counter        $xx xx xx xx (xx ...)
                    $framedata .= Helper::BigEndian2String($source_data_array['data'], 4, false);
                    break;

                case 'POPM':
                    // 4.17  POPM Popularimeter
                    //   When the counter reaches all one's, one byte is inserted in
                    //   front of the counter thus making the counter eight bits bigger
                    // Email to user   <text string> $00
                    // Rating          $xx
                    // Counter         $xx xx xx xx (xx ...)
                    if (!$this->IsWithinBitRange($source_data_array['rating'], 8, false)) {
                        $this->errors[] = 'Invalid Rating byte in '.$frame_name.' ('.$source_data_array['rating'].') (range = 0 to 255)';
                    } elseif (!IsValidEmail($source_data_array['email'])) {
                        $this->errors[] = 'Invalid Email in '.$frame_name.' ('.$source_data_array['email'].')';
                    } else {
                        $framedata .= str_replace("\x00", '', $source_data_array['email'])."\x00";
                        $framedata .= chr($source_data_array['rating']);
                        $framedata .= Helper::BigEndian2String($source_data_array['data'], 4, false);
                    }
                    break;

                case 'RBUF':
                    // 4.18  RBUF Recommended buffer size
                    // Buffer size               $xx xx xx
                    // Embedded info flag        %0000000x
                    // Offset to next tag        $xx xx xx xx
                    if (!$this->IsWithinBitRange($source_data_array['buffersize'], 24, false)) {
                        $this->errors[] = 'Invalid Buffer Size in '.$frame_name;
                    } elseif (!$this->IsWithinBitRange($source_data_array['nexttagoffset'], 32, false)) {
                        $this->errors[] = 'Invalid Offset To Next Tag in '.$frame_name;
                    } else {
                        $framedata .= Helper::BigEndian2String($source_data_array['buffersize'], 3, false);
                        $flag .= '0000000';
                        $flag .= $source_data_array['flags']['embededinfo'] ? '1' : '0';
                        $framedata .= chr(bindec($flag));
                        $framedata .= Helper::BigEndian2String($source_data_array['nexttagoffset'], 4, false);
                    }
                    break;

                case 'AENC':
                    // 4.19  AENC Audio encryption
                    // Owner identifier   <text string> $00
                    // Preview start      $xx xx
                    // Preview length     $xx xx
                    // Encryption info    <binary data>
                    if (!$this->IsWithinBitRange($source_data_array['previewstart'], 16, false)) {
                        $this->errors[] = 'Invalid Preview Start in '.$frame_name.' ('.$source_data_array['previewstart'].')';
                    } elseif (!$this->IsWithinBitRange($source_data_array['previewlength'], 16, false)) {
                        $this->errors[] = 'Invalid Preview Length in '.$frame_name.' ('.$source_data_array['previewlength'].')';
                    } else {
                        $framedata .= str_replace("\x00", '', $source_data_array['ownerid'])."\x00";
                        $framedata .= Helper::BigEndian2String($source_data_array['previewstart'], 2, false);
                        $framedata .= Helper::BigEndian2String($source_data_array['previewlength'], 2, false);
                        $framedata .= $source_data_array['encryptioninfo'];
                    }
                    break;

                case 'LINK':
                    // 4.20  LINK Linked information
                    // Frame identifier               $xx xx xx xx
                    // URL                            <text string> $00
                    // ID and additional data         <text string(s)>
                    if (!Tag\Id3v2::IsValidID3v2FrameName($source_data_array['frameid'], $this->majorversion)) {
                        $this->errors[] = 'Invalid Frame Identifier in '.$frame_name.' ('.$source_data_array['frameid'].')';
                    } elseif (!$this->IsValidURL($source_data_array['data'], true, false)) {
                        //$this->errors[] = 'Invalid URL in '.$frame_name.' ('.$source_data_array['data'].')';
                        // probably should be an error, need to rewrite IsValidURL() to handle other encodings
                        $this->warnings[] = 'Invalid URL in '.$frame_name.' ('.$source_data_array['data'].')';
                    } elseif ((($source_data_array['frameid'] == 'AENC') || ($source_data_array['frameid'] == 'APIC') || ($source_data_array['frameid'] == 'GEOB') || ($source_data_array['frameid'] == 'TXXX')) && ($source_data_array['additionaldata'] == '')) {
                        $this->errors[] = 'Content Descriptor must be specified as additional data for Frame Identifier of '.$source_data_array['frameid'].' in '.$frame_name;
                    } elseif (($source_data_array['frameid'] == 'USER') && (Tag\Id3v2::LanguageLookup($source_data_array['additionaldata'], true) == '')) {
                        $this->errors[] = 'Language must be specified as additional data for Frame Identifier of '.$source_data_array['frameid'].' in '.$frame_name;
                    } elseif (($source_data_array['frameid'] == 'PRIV') && ($source_data_array['additionaldata'] == '')) {
                        $this->errors[] = 'Owner Identifier must be specified as additional data for Frame Identifier of '.$source_data_array['frameid'].' in '.$frame_name;
                    } elseif ((($source_data_array['frameid'] == 'COMM') || ($source_data_array['frameid'] == 'SYLT') || ($source_data_array['frameid'] == 'USLT')) && ((Tag\Id3v2::LanguageLookup(substr($source_data_array['additionaldata'], 0, 3), true) == '') || (substr($source_data_array['additionaldata'], 3) == ''))) {
                        $this->errors[] = 'Language followed by Content Descriptor must be specified as additional data for Frame Identifier of '.$source_data_array['frameid'].' in '.$frame_name;
                    } else {
                        $framedata .= $source_data_array['frameid'];
                        $framedata .= str_replace("\x00", '', $source_data_array['data'])."\x00";
                        switch ($source_data_array['frameid']) {
                            case 'COMM':
                            case 'SYLT':
                            case 'USLT':
                            case 'PRIV':
                            case 'USER':
                            case 'AENC':
                            case 'APIC':
                            case 'GEOB':
                            case 'TXXX':
                                $framedata .= $source_data_array['additionaldata'];
                                break;
                            case 'ASPI':
                            case 'ETCO':
                            case 'EQU2':
                            case 'MCID':
                            case 'MLLT':
                            case 'OWNE':
                            case 'RVA2':
                            case 'RVRB':
                            case 'SYTC':
                            case 'IPLS':
                            case 'RVAD':
                            case 'EQUA':
                                // no additional data required
                                break;
                            case 'RBUF':
                                if ($this->majorversion == 3) {
                                    // no additional data required
                                } else {
                                    $this->errors[] = $source_data_array['frameid'].' is not a valid Frame Identifier in '.$frame_name.' (in ID3v2.'.$this->majorversion.')';
                                }

                            default:
                                if ((substr($source_data_array['frameid'], 0, 1) == 'T') || (substr($source_data_array['frameid'], 0, 1) == 'W')) {
                                    // no additional data required
                                } else {
                                    $this->errors[] = $source_data_array['frameid'].' is not a valid Frame Identifier in '.$frame_name.' (in ID3v2.'.$this->majorversion.')';
                                }
                                break;
                        }
                    }
                    break;

                case 'POSS':
                    // 4.21  POSS Position synchronisation frame (ID3v2.3+ only)
                    // Time stamp format         $xx
                    // Position                  $xx (xx ...)
                    if (($source_data_array['timestampformat'] < 1) || ($source_data_array['timestampformat'] > 2)) {
                        $this->errors[] = 'Invalid Time Stamp Format in '.$frame_name.' ('.$source_data_array['timestampformat'].') (valid = 1 or 2)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['position'], 32, false)) {
                        $this->errors[] = 'Invalid Position in '.$frame_name.' ('.$source_data_array['position'].') (range = 0 to 4294967295)';
                    } else {
                        $framedata .= chr($source_data_array['timestampformat']);
                        $framedata .= Helper::BigEndian2String($source_data_array['position'], 4, false);
                    }
                    break;

                case 'USER':
                    // 4.22  USER Terms of use (ID3v2.3+ only)
                    // Text encoding        $xx
                    // Language             $xx xx xx
                    // The actual text      <text string according to encoding>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].')';
                    } elseif (Tag\Id3v2::LanguageLookup($source_data_array['language'], true) == '') {
                        $this->errors[] = 'Invalid Language in '.$frame_name.' ('.$source_data_array['language'].')';
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= strtolower($source_data_array['language']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'OWNE':
                    // 4.23  OWNE Ownership frame (ID3v2.3+ only)
                    // Text encoding     $xx
                    // Price paid        <text string> $00
                    // Date of purch.    <text string>
                    // Seller            <text string according to encoding>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].')';
                    } elseif (!$this->IsANumber($source_data_array['pricepaid']['value'], false)) {
                        $this->errors[] = 'Invalid Price Paid in '.$frame_name.' ('.$source_data_array['pricepaid']['value'].')';
                    } elseif (!$this->IsValidDateStampString($source_data_array['purchasedate'])) {
                        $this->errors[] = 'Invalid Date Of Purchase in '.$frame_name.' ('.$source_data_array['purchasedate'].') (format = YYYYMMDD)';
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        $framedata .= str_replace("\x00", '', $source_data_array['pricepaid']['value'])."\x00";
                        $framedata .= $source_data_array['purchasedate'];
                        $framedata .= $source_data_array['seller'];
                    }
                    break;

                case 'COMR':
                    // 4.24  COMR Commercial frame (ID3v2.3+ only)
                    // Text encoding      $xx
                    // Price string       <text string> $00
                    // Valid until        <text string>
                    // Contact URL        <text string> $00
                    // Received as        $xx
                    // Name of seller     <text string according to encoding> $00 (00)
                    // Description        <text string according to encoding> $00 (00)
                    // Picture MIME type  <string> $00
                    // Seller logo        <binary data>
                    $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                    if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                        $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].')';
                    } elseif (!$this->IsValidDateStampString($source_data_array['pricevaliduntil'])) {
                        $this->errors[] = 'Invalid Valid Until date in '.$frame_name.' ('.$source_data_array['pricevaliduntil'].') (format = YYYYMMDD)';
                    } elseif (!$this->IsValidURL($source_data_array['contacturl'], false, true)) {
                        $this->errors[] = 'Invalid Contact URL in '.$frame_name.' ('.$source_data_array['contacturl'].') (allowed schemes: http, https, ftp, mailto)';
                    } elseif (!$this->ID3v2IsValidCOMRreceivedAs($source_data_array['receivedasid'])) {
                        $this->errors[] = 'Invalid Received As byte in '.$frame_name.' ('.$source_data_array['contacturl'].') (range = 0 to 8)';
                    } elseif (!$this->IsValidMIMEstring($source_data_array['mime'])) {
                        $this->errors[] = 'Invalid MIME Type in '.$frame_name.' ('.$source_data_array['mime'].')';
                    } else {
                        $framedata .= chr($source_data_array['encodingid']);
                        unset($pricestring);
                        foreach ($source_data_array['price'] as $key => $val) {
                            if ($this->ID3v2IsValidPriceString($key.$val['value'])) {
                                $pricestrings[] = $key.$val['value'];
                            } else {
                                $this->errors[] = 'Invalid Price String in '.$frame_name.' ('.$key.$val['value'].')';
                            }
                        }
                        $framedata .= implode('/', $pricestrings);
                        $framedata .= $source_data_array['pricevaliduntil'];
                        $framedata .= str_replace("\x00", '', $source_data_array['contacturl'])."\x00";
                        $framedata .= chr($source_data_array['receivedasid']);
                        $framedata .= $source_data_array['sellername'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['description'].Tag\Id3v2::TextEncodingTerminatorLookup($source_data_array['encodingid']);
                        $framedata .= $source_data_array['mime']."\x00";
                        $framedata .= $source_data_array['logo'];
                    }
                    break;

                case 'ENCR':
                    // 4.25  ENCR Encryption method registration (ID3v2.3+ only)
                    // Owner identifier    <text string> $00
                    // Method symbol       $xx
                    // Encryption data     <binary data>
                    if (!$this->IsWithinBitRange($source_data_array['methodsymbol'], 8, false)) {
                        $this->errors[] = 'Invalid Group Symbol in '.$frame_name.' ('.$source_data_array['methodsymbol'].') (range = 0 to 255)';
                    } else {
                        $framedata .= str_replace("\x00", '', $source_data_array['ownerid'])."\x00";
                        $framedata .= ord($source_data_array['methodsymbol']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'GRID':
                    // 4.26  GRID Group identification registration (ID3v2.3+ only)
                    // Owner identifier      <text string> $00
                    // Group symbol          $xx
                    // Group dependent data  <binary data>
                    if (!$this->IsWithinBitRange($source_data_array['groupsymbol'], 8, false)) {
                        $this->errors[] = 'Invalid Group Symbol in '.$frame_name.' ('.$source_data_array['groupsymbol'].') (range = 0 to 255)';
                    } else {
                        $framedata .= str_replace("\x00", '', $source_data_array['ownerid'])."\x00";
                        $framedata .= ord($source_data_array['groupsymbol']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'PRIV':
                    // 4.27  PRIV Private frame (ID3v2.3+ only)
                    // Owner identifier      <text string> $00
                    // The private data      <binary data>
                    $framedata .= str_replace("\x00", '', $source_data_array['ownerid'])."\x00";
                    $framedata .= $source_data_array['data'];
                    break;

                case 'SIGN':
                    // 4.28  SIGN Signature frame (ID3v2.4+ only)
                    // Group symbol      $xx
                    // Signature         <binary data>
                    if (!$this->IsWithinBitRange($source_data_array['groupsymbol'], 8, false)) {
                        $this->errors[] = 'Invalid Group Symbol in '.$frame_name.' ('.$source_data_array['groupsymbol'].') (range = 0 to 255)';
                    } else {
                        $framedata .= ord($source_data_array['groupsymbol']);
                        $framedata .= $source_data_array['data'];
                    }
                    break;

                case 'SEEK':
                    // 4.29  SEEK Seek frame (ID3v2.4+ only)
                    // Minimum offset to next tag       $xx xx xx xx
                    if (!$this->IsWithinBitRange($source_data_array['data'], 32, false)) {
                        $this->errors[] = 'Invalid Minimum Offset in '.$frame_name.' ('.$source_data_array['data'].') (range = 0 to 4294967295)';
                    } else {
                        $framedata .= Helper::BigEndian2String($source_data_array['data'], 4, false);
                    }
                    break;

                case 'ASPI':
                    // 4.30  ASPI Audio seek point index (ID3v2.4+ only)
                    // Indexed data start (S)         $xx xx xx xx
                    // Indexed data length (L)        $xx xx xx xx
                    // Number of index points (N)     $xx xx
                    // Bits per index point (b)       $xx
                    //   Then for every index point the following data is included:
                    // Fraction at index (Fi)          $xx (xx)
                    if (!$this->IsWithinBitRange($source_data_array['datastart'], 32, false)) {
                        $this->errors[] = 'Invalid Indexed Data Start in '.$frame_name.' ('.$source_data_array['datastart'].') (range = 0 to 4294967295)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['datalength'], 32, false)) {
                        $this->errors[] = 'Invalid Indexed Data Length in '.$frame_name.' ('.$source_data_array['datalength'].') (range = 0 to 4294967295)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['indexpoints'], 16, false)) {
                        $this->errors[] = 'Invalid Number Of Index Points in '.$frame_name.' ('.$source_data_array['indexpoints'].') (range = 0 to 65535)';
                    } elseif (!$this->IsWithinBitRange($source_data_array['bitsperpoint'], 8, false)) {
                        $this->errors[] = 'Invalid Bits Per Index Point in '.$frame_name.' ('.$source_data_array['bitsperpoint'].') (range = 0 to 255)';
                    } elseif ($source_data_array['indexpoints'] != count($source_data_array['indexes'])) {
                        $this->errors[] = 'Number Of Index Points does not match actual supplied data in '.$frame_name;
                    } else {
                        $framedata .= Helper::BigEndian2String($source_data_array['datastart'], 4, false);
                        $framedata .= Helper::BigEndian2String($source_data_array['datalength'], 4, false);
                        $framedata .= Helper::BigEndian2String($source_data_array['indexpoints'], 2, false);
                        $framedata .= Helper::BigEndian2String($source_data_array['bitsperpoint'], 1, false);
                        foreach ($source_data_array['indexes'] as $key => $val) {
                            $framedata .= Helper::BigEndian2String($val, ceil($source_data_array['bitsperpoint'] / 8), false);
                        }
                    }
                    break;

                case 'RGAD':
                    //   RGAD Replay Gain Adjustment
                    //   http://privatewww.essex.ac.uk/~djmrob/replaygain/
                    // Peak Amplitude                     $xx $xx $xx $xx
                    // Radio Replay Gain Adjustment        %aaabbbcd %dddddddd
                    // Audiophile Replay Gain Adjustment   %aaabbbcd %dddddddd
                    //   a - name code
                    //   b - originator code
                    //   c - sign bit
                    //   d - replay gain adjustment

                    if (($source_data_array['track_adjustment'] > 51) || ($source_data_array['track_adjustment'] < -51)) {
                        $this->errors[] = 'Invalid Track Adjustment in '.$frame_name.' ('.$source_data_array['track_adjustment'].') (range = -51.0 to +51.0)';
                    } elseif (($source_data_array['album_adjustment'] > 51) || ($source_data_array['album_adjustment'] < -51)) {
                        $this->errors[] = 'Invalid Album Adjustment in '.$frame_name.' ('.$source_data_array['album_adjustment'].') (range = -51.0 to +51.0)';
                    } elseif (!$this->ID3v2IsValidRGADname($source_data_array['raw']['track_name'])) {
                        $this->errors[] = 'Invalid Track Name Code in '.$frame_name.' ('.$source_data_array['raw']['track_name'].') (range = 0 to 2)';
                    } elseif (!$this->ID3v2IsValidRGADname($source_data_array['raw']['album_name'])) {
                        $this->errors[] = 'Invalid Album Name Code in '.$frame_name.' ('.$source_data_array['raw']['album_name'].') (range = 0 to 2)';
                    } elseif (!$this->ID3v2IsValidRGADoriginator($source_data_array['raw']['track_originator'])) {
                        $this->errors[] = 'Invalid Track Originator Code in '.$frame_name.' ('.$source_data_array['raw']['track_originator'].') (range = 0 to 3)';
                    } elseif (!$this->ID3v2IsValidRGADoriginator($source_data_array['raw']['album_originator'])) {
                        $this->errors[] = 'Invalid Album Originator Code in '.$frame_name.' ('.$source_data_array['raw']['album_originator'].') (range = 0 to 3)';
                    } else {
                        $framedata .= Helper::Float2String($source_data_array['peakamplitude'], 32);
                        $framedata .= Helper::RGADgainString($source_data_array['raw']['track_name'], $source_data_array['raw']['track_originator'], $source_data_array['track_adjustment']);
                        $framedata .= Helper::RGADgainString($source_data_array['raw']['album_name'], $source_data_array['raw']['album_originator'], $source_data_array['album_adjustment']);
                    }
                    break;

                default:
                    if ((($this->majorversion == 2) && (strlen($frame_name) != 3)) || (($this->majorversion > 2) && (strlen($frame_name) != 4))) {
                        $this->errors[] = 'Invalid frame name "'.$frame_name.'" for ID3v2.'.$this->majorversion;
                    } elseif ($frame_name{0} == 'T') {
                        // 4.2. T???  Text information frames
                        // Text encoding                $xx
                        // Information                  <text string(s) according to encoding>
                        $source_data_array['encodingid'] = (isset($source_data_array['encodingid']) ? $source_data_array['encodingid'] : $this->id3v2_default_encodingid);
                        if (!$this->ID3v2IsValidTextEncoding($source_data_array['encodingid'])) {
                            $this->errors[] = 'Invalid Text Encoding in '.$frame_name.' ('.$source_data_array['encodingid'].') for ID3v2.'.$this->majorversion;
                        } else {
                            $framedata .= chr($source_data_array['encodingid']);
                            $framedata .= $source_data_array['data'];
                        }
                    } elseif ($frame_name{0} == 'W') {
                        // 4.3. W???  URL link frames
                        // URL              <text string>
                        if (!$this->IsValidURL($source_data_array['data'], false, false)) {
                            //$this->errors[] = 'Invalid URL in '.$frame_name.' ('.$source_data_array['data'].')';
                            // probably should be an error, need to rewrite IsValidURL() to handle other encodings
                            $this->warnings[] = 'Invalid URL in '.$frame_name.' ('.$source_data_array['data'].')';
                        } else {
                            $framedata .= $source_data_array['data'];
                        }
                    } else {
                        $this->errors[] = $frame_name.' not yet supported in $this->GenerateID3v2FrameData()';
                    }
                    break;
            }
        }
        if (!empty($this->errors)) {
            return false;
        }

        return $framedata;
    }

    public function ID3v2FrameIsAllowed($frame_name, $source_data_array)
    {
        static $PreviousFrames = array();

        if ($frame_name === null) {
            // if the writing functions are called multiple times, the static array needs to be
            // cleared - this can be done by calling $this->ID3v2FrameIsAllowed(null, '')
            $PreviousFrames = array();

            return true;
        }

        if ($this->majorversion == 4) {
            switch ($frame_name) {
                case 'UFID':
                case 'AENC':
                case 'ENCR':
                case 'GRID':
                    if (!isset($source_data_array['ownerid'])) {
                        $this->errors[] = '[ownerid] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['ownerid'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same OwnerID ('.$source_data_array['ownerid'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['ownerid'];
                    }
                    break;

                case 'TXXX':
                case 'WXXX':
                case 'RVA2':
                case 'EQU2':
                case 'APIC':
                case 'GEOB':
                    if (!isset($source_data_array['description'])) {
                        $this->errors[] = '[description] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['description'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Description ('.$source_data_array['description'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['description'];
                    }
                    break;

                case 'USER':
                    if (!isset($source_data_array['language'])) {
                        $this->errors[] = '[language] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['language'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Language ('.$source_data_array['language'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['language'];
                    }
                    break;

                case 'USLT':
                case 'SYLT':
                case 'COMM':
                    if (!isset($source_data_array['language'])) {
                        $this->errors[] = '[language] not specified for '.$frame_name;
                    } elseif (!isset($source_data_array['description'])) {
                        $this->errors[] = '[description] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['language'].$source_data_array['description'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Language + Description ('.$source_data_array['language'].' + '.$source_data_array['description'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['language'].$source_data_array['description'];
                    }
                    break;

                case 'POPM':
                    if (!isset($source_data_array['email'])) {
                        $this->errors[] = '[email] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['email'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Email ('.$source_data_array['email'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['email'];
                    }
                    break;

                case 'IPLS':
                case 'MCDI':
                case 'ETCO':
                case 'MLLT':
                case 'SYTC':
                case 'RVRB':
                case 'PCNT':
                case 'RBUF':
                case 'POSS':
                case 'OWNE':
                case 'SEEK':
                case 'ASPI':
                case 'RGAD':
                    if (in_array($frame_name, $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed';
                    } else {
                        $PreviousFrames[] = $frame_name;
                    }
                    break;

                case 'LINK':
                    // this isn't implemented quite right (yet) - it should check the target frame data for compliance
                    // but right now it just allows one linked frame of each type, to be safe.
                    if (!isset($source_data_array['frameid'])) {
                        $this->errors[] = '[frameid] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['frameid'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same FrameID ('.$source_data_array['frameid'].')';
                    } elseif (in_array($source_data_array['frameid'], $PreviousFrames)) {
                        // no links to singleton tags
                        $this->errors[] = 'Cannot specify a '.$frame_name.' tag to a singleton tag that already exists ('.$source_data_array['frameid'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['frameid']; // only one linked tag of this type
                        $PreviousFrames[] = $source_data_array['frameid'];             // no non-linked singleton tags of this type
                    }
                    break;

                case 'COMR':
                    //   There may be more than one 'commercial frame' in a tag, but no two may be identical
                    // Checking isn't implemented at all (yet) - just assumes that it's OK.
                    break;

                case 'PRIV':
                case 'SIGN':
                    if (!isset($source_data_array['ownerid'])) {
                        $this->errors[] = '[ownerid] not specified for '.$frame_name;
                    } elseif (!isset($source_data_array['data'])) {
                        $this->errors[] = '[data] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['ownerid'].$source_data_array['data'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same OwnerID + Data ('.$source_data_array['ownerid'].' + '.$source_data_array['data'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['ownerid'].$source_data_array['data'];
                    }
                    break;

                default:
                    if (($frame_name{0} != 'T') && ($frame_name{0} != 'W')) {
                        $this->errors[] = 'Frame not allowed in ID3v2.'.$this->majorversion.': '.$frame_name;
                    }
                    break;
            }
        } elseif ($this->majorversion == 3) {
            switch ($frame_name) {
                case 'UFID':
                case 'AENC':
                case 'ENCR':
                case 'GRID':
                    if (!isset($source_data_array['ownerid'])) {
                        $this->errors[] = '[ownerid] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['ownerid'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same OwnerID ('.$source_data_array['ownerid'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['ownerid'];
                    }
                    break;

                case 'TXXX':
                case 'WXXX':
                case 'APIC':
                case 'GEOB':
                    if (!isset($source_data_array['description'])) {
                        $this->errors[] = '[description] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['description'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Description ('.$source_data_array['description'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['description'];
                    }
                    break;

                case 'USER':
                    if (!isset($source_data_array['language'])) {
                        $this->errors[] = '[language] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['language'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Language ('.$source_data_array['language'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['language'];
                    }
                    break;

                case 'USLT':
                case 'SYLT':
                case 'COMM':
                    if (!isset($source_data_array['language'])) {
                        $this->errors[] = '[language] not specified for '.$frame_name;
                    } elseif (!isset($source_data_array['description'])) {
                        $this->errors[] = '[description] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['language'].$source_data_array['description'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Language + Description ('.$source_data_array['language'].' + '.$source_data_array['description'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['language'].$source_data_array['description'];
                    }
                    break;

                case 'POPM':
                    if (!isset($source_data_array['email'])) {
                        $this->errors[] = '[email] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['email'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Email ('.$source_data_array['email'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['email'];
                    }
                    break;

                case 'IPLS':
                case 'MCDI':
                case 'ETCO':
                case 'MLLT':
                case 'SYTC':
                case 'RVAD':
                case 'EQUA':
                case 'RVRB':
                case 'PCNT':
                case 'RBUF':
                case 'POSS':
                case 'OWNE':
                case 'RGAD':
                    if (in_array($frame_name, $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed';
                    } else {
                        $PreviousFrames[] = $frame_name;
                    }
                    break;

                case 'LINK':
                    // this isn't implemented quite right (yet) - it should check the target frame data for compliance
                    // but right now it just allows one linked frame of each type, to be safe.
                    if (!isset($source_data_array['frameid'])) {
                        $this->errors[] = '[frameid] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['frameid'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same FrameID ('.$source_data_array['frameid'].')';
                    } elseif (in_array($source_data_array['frameid'], $PreviousFrames)) {
                        // no links to singleton tags
                        $this->errors[] = 'Cannot specify a '.$frame_name.' tag to a singleton tag that already exists ('.$source_data_array['frameid'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['frameid']; // only one linked tag of this type
                        $PreviousFrames[] = $source_data_array['frameid'];             // no non-linked singleton tags of this type
                    }
                    break;

                case 'COMR':
                    //   There may be more than one 'commercial frame' in a tag, but no two may be identical
                    // Checking isn't implemented at all (yet) - just assumes that it's OK.
                    break;

                case 'PRIV':
                    if (!isset($source_data_array['ownerid'])) {
                        $this->errors[] = '[ownerid] not specified for '.$frame_name;
                    } elseif (!isset($source_data_array['data'])) {
                        $this->errors[] = '[data] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['ownerid'].$source_data_array['data'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same OwnerID + Data ('.$source_data_array['ownerid'].' + '.$source_data_array['data'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['ownerid'].$source_data_array['data'];
                    }
                    break;

                default:
                    if (($frame_name{0} != 'T') && ($frame_name{0} != 'W')) {
                        $this->errors[] = 'Frame not allowed in ID3v2.'.$this->majorversion.': '.$frame_name;
                    }
                    break;
            }
        } elseif ($this->majorversion == 2) {
            switch ($frame_name) {
                case 'UFI':
                case 'CRM':
                case 'CRA':
                    if (!isset($source_data_array['ownerid'])) {
                        $this->errors[] = '[ownerid] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['ownerid'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same OwnerID ('.$source_data_array['ownerid'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['ownerid'];
                    }
                    break;

                case 'TXX':
                case 'WXX':
                case 'PIC':
                case 'GEO':
                    if (!isset($source_data_array['description'])) {
                        $this->errors[] = '[description] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['description'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Description ('.$source_data_array['description'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['description'];
                    }
                    break;

                case 'ULT':
                case 'SLT':
                case 'COM':
                    if (!isset($source_data_array['language'])) {
                        $this->errors[] = '[language] not specified for '.$frame_name;
                    } elseif (!isset($source_data_array['description'])) {
                        $this->errors[] = '[description] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['language'].$source_data_array['description'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Language + Description ('.$source_data_array['language'].' + '.$source_data_array['description'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['language'].$source_data_array['description'];
                    }
                    break;

                case 'POP':
                    if (!isset($source_data_array['email'])) {
                        $this->errors[] = '[email] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['email'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same Email ('.$source_data_array['email'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['email'];
                    }
                    break;

                case 'IPL':
                case 'MCI':
                case 'ETC':
                case 'MLL':
                case 'STC':
                case 'RVA':
                case 'EQU':
                case 'REV':
                case 'CNT':
                case 'BUF':
                    if (in_array($frame_name, $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed';
                    } else {
                        $PreviousFrames[] = $frame_name;
                    }
                    break;

                case 'LNK':
                    // this isn't implemented quite right (yet) - it should check the target frame data for compliance
                    // but right now it just allows one linked frame of each type, to be safe.
                    if (!isset($source_data_array['frameid'])) {
                        $this->errors[] = '[frameid] not specified for '.$frame_name;
                    } elseif (in_array($frame_name.$source_data_array['frameid'], $PreviousFrames)) {
                        $this->errors[] = 'Only one '.$frame_name.' tag allowed with the same FrameID ('.$source_data_array['frameid'].')';
                    } elseif (in_array($source_data_array['frameid'], $PreviousFrames)) {
                        // no links to singleton tags
                        $this->errors[] = 'Cannot specify a '.$frame_name.' tag to a singleton tag that already exists ('.$source_data_array['frameid'].')';
                    } else {
                        $PreviousFrames[] = $frame_name.$source_data_array['frameid']; // only one linked tag of this type
                        $PreviousFrames[] = $source_data_array['frameid'];             // no non-linked singleton tags of this type
                    }
                    break;

                default:
                    if (($frame_name{0} != 'T') && ($frame_name{0} != 'W')) {
                        $this->errors[] = 'Frame not allowed in ID3v2.'.$this->majorversion.': '.$frame_name;
                    }
                    break;
            }
        }

        if (!empty($this->errors)) {
            return false;
        }

        return true;
    }

    /**
     * @param  type    $noerrorsonly
     *
     * @return bool
     */
    public function GenerateID3v2Tag($noerrorsonly = true)
    {
        $this->ID3v2FrameIsAllowed(null, ''); // clear static array in case this isn't the first call to $this->GenerateID3v2Tag()

        $tagstring = '';
        if (is_array($this->tag_data)) {
            foreach ($this->tag_data as $frame_name => $frame_rawinputdata) {
                foreach ($frame_rawinputdata as $irrelevantindex => $source_data_array) {
                    if (Tag\Id3v2::IsValidID3v2FrameName($frame_name, $this->majorversion)) {
                        unset($frame_length);
                        unset($frame_flags);
                        $frame_data = false;
                        if ($this->ID3v2FrameIsAllowed($frame_name, $source_data_array)) {
                            if ($frame_data = $this->GenerateID3v2FrameData($frame_name, $source_data_array)) {
                                $FrameUnsynchronisation = false;
                                if ($this->majorversion >= 4) {
                                    // frame-level unsynchronisation
                                    $unsynchdata = $frame_data;
                                    if ($this->id3v2_use_unsynchronisation) {
                                        $unsynchdata = $this->Unsynchronise($frame_data);
                                    }
                                    if (strlen($unsynchdata) != strlen($frame_data)) {
                                        // unsynchronisation needed
                                        $FrameUnsynchronisation = true;
                                        $frame_data = $unsynchdata;
                                        if (isset($TagUnsynchronisation) && $TagUnsynchronisation === false) {
                                            // only set to true if ALL frames are unsynchronised
                                        } else {
                                            $TagUnsynchronisation = true;
                                        }
                                    } else {
                                        if (isset($TagUnsynchronisation)) {
                                            $TagUnsynchronisation = false;
                                        }
                                    }
                                    unset($unsynchdata);

                                    $frame_length = Helper::BigEndian2String(strlen($frame_data), 4, true);
                                } else {
                                    $frame_length = Helper::BigEndian2String(strlen($frame_data), 4, false);
                                }
                                $frame_flags = $this->GenerateID3v2FrameFlags($this->ID3v2FrameFlagsLookupTagAlter($frame_name), $this->ID3v2FrameFlagsLookupFileAlter($frame_name), false, false, false, false, $FrameUnsynchronisation, false);
                            }
                        } else {
                            $this->errors[] = 'Frame "'.$frame_name.'" is NOT allowed';
                        }
                        if ($frame_data === false) {
                            $this->errors[] = '$this->GenerateID3v2FrameData() failed for "'.$frame_name.'"';
                            if ($noerrorsonly) {
                                return false;
                            } else {
                                unset($frame_name);
                            }
                        }
                    } else {
                        // ignore any invalid frame names, including 'title', 'header', etc
                        $this->warnings[] = 'Ignoring invalid ID3v2 frame type: "'.$frame_name.'"';
                        unset($frame_name);
                        unset($frame_length);
                        unset($frame_flags);
                        unset($frame_data);
                    }
                    if (isset($frame_name) && isset($frame_length) && isset($frame_flags) && isset($frame_data)) {
                        $tagstring .= $frame_name.$frame_length.$frame_flags.$frame_data;
                    }
                }
            }

            if (!isset($TagUnsynchronisation)) {
                $TagUnsynchronisation = false;
            }
            if (($this->majorversion <= 3) && $this->id3v2_use_unsynchronisation) {
                // tag-level unsynchronisation
                $unsynchdata = $this->Unsynchronise($tagstring);
                if (strlen($unsynchdata) != strlen($tagstring)) {
                    // unsynchronisation needed
                    $TagUnsynchronisation = true;
                    $tagstring = $unsynchdata;
                }
            }

            while ($this->paddedlength < (strlen($tagstring) + Tag\Id3v2::ID3v2HeaderLength($this->majorversion))) {
                $this->paddedlength += 1024;
            }

            $footer = false; // ID3v2 footers not yet supported in GetId3Core()
            if (!$footer && ($this->paddedlength > (strlen($tagstring) + Tag\Id3v2::ID3v2HeaderLength($this->majorversion)))) {
                // pad up to $paddedlength bytes if unpadded tag is shorter than $paddedlength
                // "Furthermore it MUST NOT have any padding when a tag footer is added to the tag."
                if (($this->paddedlength - strlen($tagstring) - Tag\Id3v2::ID3v2HeaderLength($this->majorversion)) > 0) {
                    $tagstring .= str_repeat("\x00", $this->paddedlength - strlen($tagstring) - Tag\Id3v2::ID3v2HeaderLength($this->majorversion));
                }
            }
            if ($this->id3v2_use_unsynchronisation && (substr($tagstring, strlen($tagstring) - 1, 1) == "\xFF")) {
                // special unsynchronisation case:
                // if last byte == $FF then appended a $00
                $TagUnsynchronisation = true;
                $tagstring .= "\x00";
            }

            $tagheader = 'ID3';
            $tagheader .= chr($this->majorversion);
            $tagheader .= chr($this->minorversion);
            $tagheader .= $this->GenerateID3v2TagFlags(array('unsynchronisation' => $TagUnsynchronisation));
            $tagheader .= Helper::BigEndian2String(strlen($tagstring), 4, true);

            return $tagheader.$tagstring;
        }
        $this->errors[] = 'tag_data is not an array in GenerateID3v2Tag()';

        return false;
    }

    /**
     * @param  type    $pricestring
     *
     * @return bool
     */
    public function ID3v2IsValidPriceString($pricestring)
    {
        if (Tag\Id3v2::LanguageLookup(substr($pricestring, 0, 3), true) == '') {
            return false;
        } elseif (!$this->IsANumber(substr($pricestring, 3), true)) {
            return false;
        }

        return true;
    }

    /**
     * @param  type    $framename
     *
     * @return bool
     */
    public function ID3v2FrameFlagsLookupTagAlter($framename)
    {
        // unfinished
        switch ($framename) {
            case 'RGAD':
                $allow = true;
            default:
                $allow = false;
                break;
        }

        return $allow;
    }

    /**
     * @param  type    $framename
     *
     * @return bool
     */
    public function ID3v2FrameFlagsLookupFileAlter($framename)
    {
        // unfinished
        switch ($framename) {
            case 'RGAD':
                return false;
                break;

            default:
                return false;
                break;
        }
    }

    /**
     * @param  type    $eventid
     *
     * @return bool
     */
    public function ID3v2IsValidETCOevent($eventid)
    {
        if (($eventid < 0) || ($eventid > 0xFF)) {
            // outside range of 1 byte
            return false;
        } elseif (($eventid >= 0xF0) && ($eventid <= 0xFC)) {
            // reserved for future use
            return false;
        } elseif (($eventid >= 0x17) && ($eventid <= 0xDF)) {
            // reserved for future use
            return false;
        } elseif (($eventid >= 0x0E) && ($eventid <= 0x16) && ($this->majorversion == 2)) {
            // not defined in ID3v2.2
            return false;
        } elseif (($eventid >= 0x15) && ($eventid <= 0x16) && ($this->majorversion == 3)) {
            // not defined in ID3v2.3
            return false;
        }

        return true;
    }

    /**
     * @param  type    $contenttype
     *
     * @return bool
     */
    public function ID3v2IsValidSYLTtype($contenttype)
    {
        if (($contenttype >= 0) && ($contenttype <= 8) && ($this->majorversion == 4)) {
            return true;
        } elseif (($contenttype >= 0) && ($contenttype <= 6) && ($this->majorversion == 3)) {
            return true;
        }

        return false;
    }

    /**
     * @param  type    $channeltype
     *
     * @return bool
     */
    public function ID3v2IsValidRVA2channeltype($channeltype)
    {
        if (($channeltype >= 0) && ($channeltype <= 8) && ($this->majorversion == 4)) {
            return true;
        }

        return false;
    }

    /**
     * @param  type    $picturetype
     *
     * @return bool
     */
    public function ID3v2IsValidAPICpicturetype($picturetype)
    {
        if (($picturetype >= 0) && ($picturetype <= 0x14) && ($this->majorversion >= 2) && ($this->majorversion <= 4)) {
            return true;
        }

        return false;
    }

    /**
     * @param  type    $imageformat
     *
     * @return bool
     */
    public function ID3v2IsValidAPICimageformat($imageformat)
    {
        if ($imageformat == '-->') {
            return true;
        } elseif ($this->majorversion == 2) {
            if ((strlen($imageformat) == 3) && ($imageformat == strtoupper($imageformat))) {
                return true;
            }
        } elseif (($this->majorversion == 3) || ($this->majorversion == 4)) {
            if ($this->IsValidMIMEstring($imageformat)) {
                return true;
            }
        }

        return false;
    }

    /**
     * @param  type    $receivedas
     *
     * @return bool
     */
    public function ID3v2IsValidCOMRreceivedAs($receivedas)
    {
        if (($this->majorversion >= 3) && ($receivedas >= 0) && ($receivedas <= 8)) {
            return true;
        }

        return false;
    }

    /**
     * @param  type    $RGADname
     *
     * @return bool
     */
    public function ID3v2IsValidRGADname($RGADname)
    {
        if (($RGADname >= 0) && ($RGADname <= 2)) {
            return true;
        }

        return false;
    }

    /**
     * @param  type    $RGADoriginator
     *
     * @return bool
     */
    public function ID3v2IsValidRGADoriginator($RGADoriginator)
    {
        if (($RGADoriginator >= 0) && ($RGADoriginator <= 3)) {
            return true;
        }

        return false;
    }

    /**
     * @staticvar array $ID3v2IsValidTextEncoding_cache
     *
     * @param  type $textencodingbyte
     *
     * @return type
     */
    public function ID3v2IsValidTextEncoding($textencodingbyte)
    {
        static $ID3v2IsValidTextEncoding_cache = array(
            2 => array(true, true),
            3 => array(true, true),
            4 => array(true, true, true, true), );

        return isset($ID3v2IsValidTextEncoding_cache[$this->majorversion][$textencodingbyte]);
    }

    /**
     * @param  type   $data
     *
     * @return string
     */
    public function Unsynchronise($data)
    {
        // Whenever a false synchronisation is found within the tag, one zeroed
        // byte is inserted after the first false synchronisation byte. The
        // format of a correct sync that should be altered by ID3 encoders is as
        // follows:
        //      %11111111 111xxxxx
        // And should be replaced with:
        //      %11111111 00000000 111xxxxx
        // This has the side effect that all $FF 00 combinations have to be
        // altered, so they won't be affected by the decoding process. Therefore
        // all the $FF 00 combinations have to be replaced with the $FF 00 00
        // combination during the unsynchronisation.

        $data = str_replace("\xFF\x00", "\xFF\x00\x00", $data);
        $unsyncheddata = '';
        $datalength = strlen($data);
        for ($i = 0; $i < $datalength; ++$i) {
            $thischar = $data{$i};
            $unsyncheddata .= $thischar;
            if ($thischar == "\xFF") {
                $nextchar = ord($data{$i + 1});
                if (($nextchar & 0xE0) == 0xE0) {
                    // previous byte = 11111111, this byte = 111?????
                    $unsyncheddata .= "\x00";
                }
            }
        }

        return $unsyncheddata;
    }

    /**
     * @param  type    $var
     *
     * @return bool
     */
    public function is_hash($var)
    {
        // written by dev-nullØchristophe*vg
        // taken from http://www.php.net/manual/en/function.array-merge-recursive.php
        if (is_array($var)) {
            $keys = array_keys($var);
            $all_num = true;
            for ($i = 0; $i < count($keys); ++$i) {
                if (is_string($keys[$i])) {
                    return true;
                }
            }
        }

        return false;
    }

    /**
     * @param  type $arr1
     * @param  type $arr2
     *
     * @return type
     */
    public function array_join_merge($arr1, $arr2)
    {
        // written by dev-nullØchristophe*vg
        // taken from http://www.php.net/manual/en/function.array-merge-recursive.php
        if (is_array($arr1) && is_array($arr2)) {
            // the same -> merge
            $new_array = array();

            if ($this->is_hash($arr1) && $this->is_hash($arr2)) {
                // hashes -> merge based on keys
                $keys = array_merge(array_keys($arr1), array_keys($arr2));
                foreach ($keys as $key) {
                    $new_array[$key] = $this->array_join_merge((isset($arr1[$key]) ? $arr1[$key] : ''), (isset($arr2[$key]) ? $arr2[$key] : ''));
                }
            } else {
                // two real arrays -> merge
                $new_array = array_reverse(array_unique(array_reverse(array_merge($arr1, $arr2))));
            }

            return $new_array;
        } else {
            // not the same ... take new one if defined, else the old one stays
            return $arr2 ? $arr2 : $arr1;
        }
    }

    /**
     * @param  type    $mimestring
     *
     * @return bool
     */
    public function IsValidMIMEstring($mimestring)
    {
        if ((strlen($mimestring) >= 3) && (strpos($mimestring, '/') > 0) && (strpos($mimestring, '/') < (strlen($mimestring) - 1))) {
            return true;
        }

        return false;
    }

    /**
     * @param  type    $number
     * @param  type    $maxbits
     * @param  type    $signed
     *
     * @return bool
     */
    public function IsWithinBitRange($number, $maxbits, $signed = false)
    {
        if ($signed) {
            if (($number > (0 - pow(2, $maxbits - 1))) && ($number <= pow(2, $maxbits - 1))) {
                return true;
            }
        } else {
            if (($number >= 0) && ($number <= pow(2, $maxbits))) {
                return true;
            }
        }

        return false;
    }

    /**
     * @param  type $url
     *
     * @return type
     */
    public function safe_parse_url($url)
    {
        $parts = @parse_url($url);
        $parts['scheme'] = (isset($parts['scheme']) ? $parts['scheme'] : '');
        $parts['host'] = (isset($parts['host'])   ? $parts['host']   : '');
        $parts['user'] = (isset($parts['user'])   ? $parts['user']   : '');
        $parts['pass'] = (isset($parts['pass'])   ? $parts['pass']   : '');
        $parts['path'] = (isset($parts['path'])   ? $parts['path']   : '');
        $parts['query'] = (isset($parts['query'])  ? $parts['query']  : '');

        return $parts;
    }

    /**
     * @param  type    $url
     * @param  type    $allowUserPass
     *
     * @return bool
     */
    public function IsValidURL($url, $allowUserPass = false)
    {
        if ($url == '') {
            return false;
        }
        if ($allowUserPass !== true) {
            if (strstr($url, '@')) {
                // in the format http://user:pass@example.com  or http://user@example.com
                // but could easily be somebody incorrectly entering an email address in place of a URL
                return false;
            }
        }
        if ($parts = $this->safe_parse_url($url)) {
            if (($parts['scheme'] != 'http') && ($parts['scheme'] != 'https') && ($parts['scheme'] != 'ftp') && ($parts['scheme'] != 'gopher')) {
                return false;
            } elseif (!preg_match('#^[[:alnum:]]([-.]?[0-9a-z])*\\.[a-z]{2,3}$#i', $parts['host'], $regs) && !preg_match('#^[0-9]{1,3}(\\.[0-9]{1,3}){3}$#', $parts['host'])) {
                return false;
            } elseif (!preg_match('#^([[:alnum:]-]|[\\_])*$#i', $parts['user'], $regs)) {
                return false;
            } elseif (!preg_match('#^([[:alnum:]-]|[\\_])*$#i', $parts['pass'], $regs)) {
                return false;
            } elseif (!preg_match('#^[[:alnum:]/_\\.@~-]*$#i', $parts['path'], $regs)) {
                return false;
            } elseif (!empty($parts['query']) && !preg_match('#^[[:alnum:]?&=+:;_()%\\#/,\\.-]*$#i', $parts['query'], $regs)) {
                return false;
            } else {
                return true;
            }
        }

        return false;
    }

    /**
     * @staticvar array $ID3v2ShortFrameNameLookup
     *
     * @param  type $majorversion
     * @param  type $long_description
     *
     * @return type
     */
    public static function ID3v2ShortFrameNameLookup($majorversion, $long_description)
    {
        $long_description = str_replace(' ', '_', strtolower(trim($long_description)));
        static $ID3v2ShortFrameNameLookup = array();
        if (empty($ID3v2ShortFrameNameLookup)) {

            // The following are unique to ID3v2.2
            $ID3v2ShortFrameNameLookup[2]['comment'] = 'COM';
            $ID3v2ShortFrameNameLookup[2]['album'] = 'TAL';
            $ID3v2ShortFrameNameLookup[2]['beats_per_minute'] = 'TBP';
            $ID3v2ShortFrameNameLookup[2]['composer'] = 'TCM';
            $ID3v2ShortFrameNameLookup[2]['genre'] = 'TCO';
            $ID3v2ShortFrameNameLookup[2]['itunescompilation'] = 'TCP';
            $ID3v2ShortFrameNameLookup[2]['copyright'] = 'TCR';
            $ID3v2ShortFrameNameLookup[2]['encoded_by'] = 'TEN';
            $ID3v2ShortFrameNameLookup[2]['language'] = 'TLA';
            $ID3v2ShortFrameNameLookup[2]['length'] = 'TLE';
            $ID3v2ShortFrameNameLookup[2]['original_artist'] = 'TOA';
            $ID3v2ShortFrameNameLookup[2]['original_filename'] = 'TOF';
            $ID3v2ShortFrameNameLookup[2]['original_lyricist'] = 'TOL';
            $ID3v2ShortFrameNameLookup[2]['original_album_title'] = 'TOT';
            $ID3v2ShortFrameNameLookup[2]['artist'] = 'TP1';
            $ID3v2ShortFrameNameLookup[2]['band'] = 'TP2';
            $ID3v2ShortFrameNameLookup[2]['conductor'] = 'TP3';
            $ID3v2ShortFrameNameLookup[2]['remixer'] = 'TP4';
            $ID3v2ShortFrameNameLookup[2]['publisher'] = 'TPB';
            $ID3v2ShortFrameNameLookup[2]['isrc'] = 'TRC';
            $ID3v2ShortFrameNameLookup[2]['tracknumber'] = 'TRK';
            $ID3v2ShortFrameNameLookup[2]['size'] = 'TSI';
            $ID3v2ShortFrameNameLookup[2]['encoder_settings'] = 'TSS';
            $ID3v2ShortFrameNameLookup[2]['description'] = 'TT1';
            $ID3v2ShortFrameNameLookup[2]['title'] = 'TT2';
            $ID3v2ShortFrameNameLookup[2]['subtitle'] = 'TT3';
            $ID3v2ShortFrameNameLookup[2]['lyricist'] = 'TXT';
            $ID3v2ShortFrameNameLookup[2]['user_text'] = 'TXX';
            $ID3v2ShortFrameNameLookup[2]['year'] = 'TYE';
            $ID3v2ShortFrameNameLookup[2]['unique_file_identifier'] = 'UFI';
            $ID3v2ShortFrameNameLookup[2]['unsynchronised_lyrics'] = 'ULT';
            $ID3v2ShortFrameNameLookup[2]['url_file'] = 'WAF';
            $ID3v2ShortFrameNameLookup[2]['url_artist'] = 'WAR';
            $ID3v2ShortFrameNameLookup[2]['url_source'] = 'WAS';
            $ID3v2ShortFrameNameLookup[2]['copyright_information'] = 'WCP';
            $ID3v2ShortFrameNameLookup[2]['url_publisher'] = 'WPB';
            $ID3v2ShortFrameNameLookup[2]['url_user'] = 'WXX';

            // The following are common to ID3v2.3 and ID3v2.4
            $ID3v2ShortFrameNameLookup[3]['audio_encryption'] = 'AENC';
            $ID3v2ShortFrameNameLookup[3]['attached_picture'] = 'APIC';
            $ID3v2ShortFrameNameLookup[3]['comment'] = 'COMM';
            $ID3v2ShortFrameNameLookup[3]['commercial'] = 'COMR';
            $ID3v2ShortFrameNameLookup[3]['encryption_method_registration'] = 'ENCR';
            $ID3v2ShortFrameNameLookup[3]['event_timing_codes'] = 'ETCO';
            $ID3v2ShortFrameNameLookup[3]['general_encapsulated_object'] = 'GEOB';
            $ID3v2ShortFrameNameLookup[3]['group_identification_registration'] = 'GRID';
            $ID3v2ShortFrameNameLookup[3]['linked_information'] = 'LINK';
            $ID3v2ShortFrameNameLookup[3]['music_cd_identifier'] = 'MCDI';
            $ID3v2ShortFrameNameLookup[3]['mpeg_location_lookup_table'] = 'MLLT';
            $ID3v2ShortFrameNameLookup[3]['ownership'] = 'OWNE';
            $ID3v2ShortFrameNameLookup[3]['play_counter'] = 'PCNT';
            $ID3v2ShortFrameNameLookup[3]['popularimeter'] = 'POPM';
            $ID3v2ShortFrameNameLookup[3]['position_synchronisation'] = 'POSS';
            $ID3v2ShortFrameNameLookup[3]['private'] = 'PRIV';
            $ID3v2ShortFrameNameLookup[3]['recommended_buffer_size'] = 'RBUF';
            $ID3v2ShortFrameNameLookup[3]['reverb'] = 'RVRB';
            $ID3v2ShortFrameNameLookup[3]['synchronised_lyrics'] = 'SYLT';
            $ID3v2ShortFrameNameLookup[3]['synchronised_tempo_codes'] = 'SYTC';
            $ID3v2ShortFrameNameLookup[3]['album'] = 'TALB';
            $ID3v2ShortFrameNameLookup[3]['beats_per_minute'] = 'TBPM';
            $ID3v2ShortFrameNameLookup[3]['itunescompilation'] = 'TCMP';
            $ID3v2ShortFrameNameLookup[3]['composer'] = 'TCOM';
            $ID3v2ShortFrameNameLookup[3]['genre'] = 'TCON';
            $ID3v2ShortFrameNameLookup[3]['copyright'] = 'TCOP';
            $ID3v2ShortFrameNameLookup[3]['playlist_delay'] = 'TDLY';
            $ID3v2ShortFrameNameLookup[3]['encoded_by'] = 'TENC';
            $ID3v2ShortFrameNameLookup[3]['lyricist'] = 'TEXT';
            $ID3v2ShortFrameNameLookup[3]['file_type'] = 'TFLT';
            $ID3v2ShortFrameNameLookup[3]['content_group_description'] = 'TIT1';
            $ID3v2ShortFrameNameLookup[3]['title'] = 'TIT2';
            $ID3v2ShortFrameNameLookup[3]['subtitle'] = 'TIT3';
            $ID3v2ShortFrameNameLookup[3]['initial_key'] = 'TKEY';
            $ID3v2ShortFrameNameLookup[3]['language'] = 'TLAN';
            $ID3v2ShortFrameNameLookup[3]['length'] = 'TLEN';
            $ID3v2ShortFrameNameLookup[3]['media_type'] = 'TMED';
            $ID3v2ShortFrameNameLookup[3]['original_album_title'] = 'TOAL';
            $ID3v2ShortFrameNameLookup[3]['original_filename'] = 'TOFN';
            $ID3v2ShortFrameNameLookup[3]['original_lyricist'] = 'TOLY';
            $ID3v2ShortFrameNameLookup[3]['original_artist'] = 'TOPE';
            $ID3v2ShortFrameNameLookup[3]['file_owner'] = 'TOWN';
            $ID3v2ShortFrameNameLookup[3]['artist'] = 'TPE1';
            $ID3v2ShortFrameNameLookup[3]['band'] = 'TPE2';
            $ID3v2ShortFrameNameLookup[3]['conductor'] = 'TPE3';
            $ID3v2ShortFrameNameLookup[3]['remixer'] = 'TPE4';
            $ID3v2ShortFrameNameLookup[3]['part_of_a_set'] = 'TPOS';
            $ID3v2ShortFrameNameLookup[3]['publisher'] = 'TPUB';
            $ID3v2ShortFrameNameLookup[3]['tracknumber'] = 'TRCK';
            $ID3v2ShortFrameNameLookup[3]['internet_radio_station_name'] = 'TRSN';
            $ID3v2ShortFrameNameLookup[3]['internet_radio_station_owner'] = 'TRSO';
            $ID3v2ShortFrameNameLookup[3]['isrc'] = 'TSRC';
            $ID3v2ShortFrameNameLookup[3]['encoder_settings'] = 'TSSE';
            $ID3v2ShortFrameNameLookup[3]['user_text'] = 'TXXX';
            $ID3v2ShortFrameNameLookup[3]['unique_file_identifier'] = 'UFID';
            $ID3v2ShortFrameNameLookup[3]['terms_of_use'] = 'USER';
            $ID3v2ShortFrameNameLookup[3]['unsynchronised_lyrics'] = 'USLT';
            $ID3v2ShortFrameNameLookup[3]['commercial'] = 'WCOM';
            $ID3v2ShortFrameNameLookup[3]['copyright_information'] = 'WCOP';
            $ID3v2ShortFrameNameLookup[3]['url_file'] = 'WOAF';
            $ID3v2ShortFrameNameLookup[3]['url_artist'] = 'WOAR';
            $ID3v2ShortFrameNameLookup[3]['url_source'] = 'WOAS';
            $ID3v2ShortFrameNameLookup[3]['url_station'] = 'WORS';
            $ID3v2ShortFrameNameLookup[3]['payment'] = 'WPAY';
            $ID3v2ShortFrameNameLookup[3]['url_publisher'] = 'WPUB';
            $ID3v2ShortFrameNameLookup[3]['url_user'] = 'WXXX';

            // The above are common to ID3v2.3 and ID3v2.4
            // so copy them to ID3v2.4 before adding specifics for 2.3 and 2.4
            $ID3v2ShortFrameNameLookup[4] = $ID3v2ShortFrameNameLookup[3];

            // The following are unique to ID3v2.3
            $ID3v2ShortFrameNameLookup[3]['equalisation'] = 'EQUA';
            $ID3v2ShortFrameNameLookup[3]['involved_people_list'] = 'IPLS';
            $ID3v2ShortFrameNameLookup[3]['relative_volume_adjustment'] = 'RVAD';
            $ID3v2ShortFrameNameLookup[3]['date'] = 'TDAT';
            $ID3v2ShortFrameNameLookup[3]['time'] = 'TIME';
            $ID3v2ShortFrameNameLookup[3]['original_release_year'] = 'TORY';
            $ID3v2ShortFrameNameLookup[3]['recording_dates'] = 'TRDA';
            $ID3v2ShortFrameNameLookup[3]['size'] = 'TSIZ';
            $ID3v2ShortFrameNameLookup[3]['year'] = 'TYER';

            // The following are unique to ID3v2.4
            $ID3v2ShortFrameNameLookup[4]['audio_seek_point_index'] = 'ASPI';
            $ID3v2ShortFrameNameLookup[4]['equalisation'] = 'EQU2';
            $ID3v2ShortFrameNameLookup[4]['relative_volume_adjustment'] = 'RVA2';
            $ID3v2ShortFrameNameLookup[4]['seek'] = 'SEEK';
            $ID3v2ShortFrameNameLookup[4]['signature'] = 'SIGN';
            $ID3v2ShortFrameNameLookup[4]['encoding_time'] = 'TDEN';
            $ID3v2ShortFrameNameLookup[4]['original_release_time'] = 'TDOR';
            $ID3v2ShortFrameNameLookup[4]['recording_time'] = 'TDRC';
            $ID3v2ShortFrameNameLookup[4]['release_time'] = 'TDRL';
            $ID3v2ShortFrameNameLookup[4]['tagging_time'] = 'TDTG';
            $ID3v2ShortFrameNameLookup[4]['involved_people_list'] = 'TIPL';
            $ID3v2ShortFrameNameLookup[4]['musician_credits_list'] = 'TMCL';
            $ID3v2ShortFrameNameLookup[4]['mood'] = 'TMOO';
            $ID3v2ShortFrameNameLookup[4]['produced_notice'] = 'TPRO';
            $ID3v2ShortFrameNameLookup[4]['album_sort_order'] = 'TSOA';
            $ID3v2ShortFrameNameLookup[4]['performer_sort_order'] = 'TSOP';
            $ID3v2ShortFrameNameLookup[4]['title_sort_order'] = 'TSOT';
            $ID3v2ShortFrameNameLookup[4]['set_subtitle'] = 'TSST';
        }

        return (isset($ID3v2ShortFrameNameLookup[$majorversion][strtolower($long_description)]) ? $ID3v2ShortFrameNameLookup[$majorversion][strtolower($long_description)] : '');
    }
}
